The Stihl Part # 1129 120 3400 Filter Base is a new OEM air filter designed specifically for 2-stroke gasoline-powered chainsaws. Made of durable black plastic, this filter base is compatible with Stihl chainsaw models and comes as a single piece in the pack. It requires no assembly and is a reliable replacement part for keeping your chainsaw running smoothly in the yard, garden, or outdoor living spaces.